Organic dye lasers with significant tunability in the visible wavelengths (e.g., covering the spectral region from ultraviolet to the near infrared) have attracted interest for many years due to their low-cost processing, flexible choice of substrates, and emission cross-sections. While practical implementation advantages would be realized by electrically-pumped organic semiconductor lasers, to date such lasers remain largely a theoretical curiosity and difficult to implement. This difficulty is due at least in part to the high thresholds of such lasers which are challenging to attain, particularly given large losses at the electrical contacts used to pump the organic semiconductor, low charge-carrier mobility in organic materials, and efficient exciton annihilation process in solid-state organic media.
One conventional approach for realizing organic lasers is the hybrid electrically-pumped organic laser. These lasers are optically pumped by small, electrically-driven inorganic diode lasers, which mitigates some of the challenges associated with direct electrically-pumped laser as discussed above. In any event, while optically-pumped organic lasers have been widely demonstrated, lasing is only possible with high peak power excitation sources of short pulses; furthermore, there has been no realization or demonstration of continuous-wave (CW) operated organic lasers without liquid dye circulation. This is because, in conventional dye lasers, continuous-wave pumping photobleaches the organic dye medium. Thus, to provide a continuous-wave output, the dye medium must be circulated through the excitation beam, e.g., in the form or a stream of liquid or a spinning disc of solid-state material.